1. Field of the Invention
This invention relates to a nozzle for spraying a medium under pressure with a selectable form of jet, comprising a casing having a bore for passage of the medium, an outlet aperture at the end of this bore, and a knife-edge body which is mounted for rotation transversely to the direction of the jet and whose rear knife edge is adapted to penetrate to a greater or lesser depth into the jet passing out of the bore in order to fan the jet outwardly.
In many applications, for example in high-pressure cleaning machines the need arises for a medium which is under pressure and which is supplied through a pipe, for example a cleaning liquid mixed with chemicals, to be discharged in varying amounts, with variable pressure, and with a selectable form of jet. For example, when removing obstinate dirt, such as in the cleaning of stables or heavily soiled building machines, a high impact pressure is necessary in order to effect thorough cleaning. This high impact pressure is achieved by directing the cleaning liquid with a high rate of flow, a high spray pressure, and in the form of a compact circular jet, onto the surface which is to be cleaned. For cleaning large surfaces, for example building faces, swimming baths, or floors, a flat jet and a large amount of water are required. This flat jet achieves a high surface cleaning power, and the detached dirt is thoroughly flushed away by the large amount of liquid. When cleaning sensitive surfaces, for example tiled walls, the pressure of the flat jet must be reduced in order to avoid damage.
For the disinfection of the cleaned surfaces a jet in the form of a spray mist is required. With a spray mist of this kind, there is fine uniform distribution of disinfectant liquid over the surfaces to be disinfected.
2. Description of the Prior Art
In order to provide these numerous variations, nozzle systems are known in which it is possible to change over from one nozzle to another by operating a slide. The various supply passages to the nozzles are sealed relative to one another by means of O-ring seals. The disadvantage of this arrangement is that it is possible to change over only to one, two, or three predetermined jet forms and corresponding spray nozzles. Continuously variable regulation of the three components: spray pressure, spray flow and jet shape is not possible in these arrangements.
Rotary change-over nozzles are also known in which four different nozzle openings giving different jet angles are provided in a nozzle disc, which is turned by means of a seal which pressed resiliently into contact, until the desired nozzle opening lies above the liquid supply hole. Continuously variable adaptation to the cleaning task is not possible with this arrangement.
The problem underlying the invention is that of so improving a nozzle of the kind defined that the amount and the pressure of the medium delivered, and also the shape of the jet, can be continuously varied.